EP 0475219 B1 19950621 - Infrared intrusion detector.
Title (en)
Infrared intrusion detector.
Title (de)
Infraroteindringdetektor.
Title (fr)
Détecteur d'intrusion à infrarouge.
Publication
Application
Priority
CH 286390 A 19900905
Abstract (en)
[origin: EP0475219A1] In a passive infrared intrusion detector, which evaluates the body radiation of an intruder with the aid of a dual sensor (3) having two sensor elements (8, 9) in a differential circuit in order to give an alarm signal, an attempt to put the detector out of action by covering or spraying the radiation entry window (2) is detected and signalled by a monitoring beam path from an infrared radiation source (7) through the window (2) via a further optical system (6) to the sensor (3). In order to achieve a different irradiation of the two sensor elements (8, 9), this optical system (6) generates at the site of the sensor (3) irradiation having an intensity which decreases gradually to the sides. If the sensor elements (8, 9) are located laterally offset on the decreasing edges of the irradiation curve, their irradiation differs without the need for a precise adjustment. This can be achieved, for example, by forming aspherical mirrors, or as segmented mirrors (6.1, 6.2, ..., 6.5), which form at the sensor site overlapping irradiation spots (B1, B2, ..., B5) which overall have a stepped intensity curve. If the step width is not larger than the spacing (ds) of the sensor elements (8, 9), the two sensor elements (8, 9) necessarily receive a different irradiation. <IMAGE>
IPC 1-7
IPC 8 full level
G08B 29/04 (2006.01)
CPC (source: EP)
G08B 29/046 (2013.01)
Designated contracting state (EPC)
AT BE CH DE DK ES FR GB IT LI LU NL SE
DOCDB simple family (publication)
EP 0475219 A1 19920318; EP 0475219 B1 19950621; AT E124160 T1 19950715; CH 680882 A5 19921130; DE 59105775 D1 19950727
DOCDB simple family (application)
EP 91114645 A 19910830; AT 91114645 T 19910830; CH 286390 A 19900905; DE 59105775 T 19910830